Noriji Taba

Functional disorders in the peripheral neuromuscular system induced by gonyautoxins in rabbits.

The effects of gonyautoxins (GTXs) on the neuromuscular system in rabbits were examined. M waves were evoked by electric stimulation on the tibial nerve and recorded mainly from the plantar interosseous muscle. Intravenous administration of GTXs decreased the amplitude and prolonged both latency and duration of M waves, while showed little effect on the motor nerve conduction velocity. These results suggest that GTXs have inhibitory effects on the peripheral neuromuscular system, mainly on the neuromuscular transmission.

Arrhythmic and hypotensive actions of gonyautoxins in rabbits.

The effects of gonyautoxins (GTXs), the major component of paralytic shellfish poison in Japan, on cardiovascular system in rabbits were examined by means of the electrocardiogram (ECG) pattern and the arterial pressure changes. The intravenous administration of GTXs produced transient arrhythmia and hypotension. GTXs induced prolongation of P-R and QRS intervals in the ECG, which was prone to initiate paroxysmal ventricular tachycardia, fibrillation and flutter in a large amount of GTXs. Similar results were observed in vagotomized rabbits.